Bloodied police uniforms were scattered with the crumpled metal hulk of the car bomb on the charred street in the aftermath of the bombing, footage from the Associated Press Television News showed.
Elsewhere in the country on Monday, 15 people were killed and about 30 wounded in a suicide car bombing against a joint US-Iraqi patrol in the centre of the northern Iraqi city of Mosul, police said.
"A suicide bomber blew his car up in the path of a joint patrol between Iraqi police and the American military in Mosul al-Jadida," a police officer at the scene was reported by the AFP news agency as saying.
The interior minister said the majority of the victims were policemen.
The latest bombings follow the Iraqi parliament approval of a security pact with the US that lets American forces remain in Iraq for three more years.